My Biolectric 52kw AD Plant

[Kirk]

there's not many of yours out there or is there don't know to much about them

I used a different company to chippy and had no problems, I think I was was there 9th one and they have Instlled 2 more since and have taken over some that the other company sold.

So that with the company chippy used prob makes about 15-20 plants in the U.K. now I would have thought.

I think that is quite a lot from one manufacturer?

 

[Kirk]

No there's not many but I'd say there's at least 15 by now. Yes I got it tested. I just used a figure of 45 m3 of gas per tonne of slurry I think

Is that biogas or methane gas?

I tested my slurry with 2 different labs and each one gave me different units of gas per tonne

 

[Mucktogold]

There's a reason why it's annoyed me so much which is because the exact same thing happened to me when I bought my dragon heat boiler butting was worse because they went bust as well

Pity that happened, thought Dragon were still going? Liked there design, solidly built. Heard about farms who were sold digesters that produced less gas than the sales literature, not much they can do about it now.

No there's not many but I'd say there's at least 15 by now. Yes I got it tested. I just used a figure of 45 m3 of gas per tonne of slurry I think

Wow, 45m3 that's truly a world record! Did Portgester sell it to you using these figures?
For the UK see http://www.biogas-info.co.uk/about/feedstocks/
and Ireland http://www.seai.ie/Renewables/Bioen...s_of_Anaerobic_Digestion/Gas_Yields_Table.pdf

 

[Mucktogold]

I used a different company to chippy and had no problems, I think I was was there 9th one and they have Instlled 2 more since and have taken over some that the other company sold.

So that with the company chippy used prob makes about 15-20 plants in the U.K. now I would have thought.

I think that is quite a lot from one manufacturer?

Several German AD firms will not build anything during the winter, they wait until the spring. Something to do with H&S?

 

[Chippy]

Oops I read the wrong bit. It was 28m3 of biogas!

 

[Chippy]

Yes dragon heat still going under another name and yes it's a good boiler but hell there an unorganised company. Once again we installed it with some help because they were just never going to get round to it and i incurred a RHI price drop thanks to them [emoji35]

 

[Kirk]

Several German AD firms will not build anything during the winter, they wait until the spring. Something to do with H&S?

a lot of the German ad plants use concrete tanks, so maybe too cold to pour?

ours is a metal tank with a liner

 

[Mucktogold]

Oops I read the wrong bit. It was 28m3 of biogas!

The data sheet posted earlier shows
DS(%) sample: 7%
ODS(%) sample: 7%
BGP sample: 46.3 Does that mean bio gas percent?
ODS should be around 70 to 90% of DS or 5 to 6% if its % of sample. If BGP is 46.3, the 60% methane in the biogas would be around 27.8%.

 

[Chippy]

I never did understand the results back from the lab

 

[Mucktogold]

I never did understand the results back from the lab

Who did the lab results showing 46.3% bio gas, was it Portagester, Bioelectric or Solcap?

 

[Chippy]

Who did the lab results showing 46.3% bio gas, was it Portagester, Bioelectric or Solcap?

I've already said it was 28m3 not 48. I sent the sample myself to Livelab and here's some more results

 

[mawleymoos]

What is yours doing now? How much digestate did you import? How full is it now, and are you producing electric yet? Thanks

 

[Chippy]

Mines running for around 6 hours a day and we only just filled it yesterday so soon it will start pumping digestate out. We imported 6 artic loads. Yes it's producing lecy but not checked meter for a while so not sure what it's got to but temperature only at 25 so still got another 17 degrees to raise it yet

 

[Digester Man]

I have never had it tested, but always thought cattle slurry was in the region of 15-20m3 of biogas per ton, after all it is nearly 95% water. Based on that, it would take 25-30 tons of slurry per day to make 52kw per hour which is over 2 million gallons a year.

Will be interesting to see how you get on, looks a very tidy unit. Good luck with it. Will be interesting to see if there is much odour left in the digestate, we find there is hardly any smell off ours (fed silage and whole crop) compared to raw cattle slurry.

 

[Kirk]

I have never had it tested, but always thought cattle slurry was in the region of 15-20m3 of biogas per ton, after all it is nearly 95% water. Based on that, it would take 25-30 tons of slurry per day to make 52kw per hour which is over 2 million gallons a year.

Will be interesting to see how you get on, looks a very tidy unit. Good luck with it. Will be interesting to see if there is much odour left in the digestate, we find there is hardly any smell off ours (fed silage and whole crop) compared to raw cattle slurry.

what retention time are you using?

 

[thesilentone]

Oops I read the wrong bit. It was 28m3 of biogas!

No, you've read it right, it says.

The BMP (Biomethane Potential) is 28.67m3 CH4/t (after 20 days)
The Biogas production will be 46.30 m3/ton

However, I get a Ch4 of 62%

Should have added, your result you show is not for Slurry alone, but Maize, Slurry and Glycerol

 

[Mucktogold]

No, you've read it right, it says.

The BMP (Biomethane Potential) is 28.67m3 CH4/t (after 20 days)
The Biogas production will be 46.30 m3/ton

However, I get a Ch4 of 62%

Should have added, your result you show is not for Slurry alone, but Maize, Slurry and Glycerol

Does that mean the biogas from the slurry alone is roughly half that of slurry plus innoculum ?

 

[thesilentone]

Does that mean the biogas from the slurry alone is roughly half that of slurry plus innoculum ?

The word inoculum used above-could have been sample.

Given the sample is from maize, grass, glycerol and slurry. The CH4 from slurry will make up around 10% if all quantities were equal (which they won't be)
As we do not know what the qty breakdowns in the sample are, we cannot guess at each BMP output.

 

[Digester Man]

what retention time are you using?

It has been calculated as being in the region of 130 days, the technology we went for has probably one of the longest retention periods around because it is a very simple system (no macerators or fancy pre mix tanks) and relies on letting the bacteria do all the work.

 

[thesilentone]

Interesting area, and one we can all benefit from knowing more about is retention time, or hydraulic retention time. Why do some have different times to others ? What is best ? What are the limits ?

Calculating residency time in the tanks for the feed-stock is complex. There are several factors to consider:

1) Organic Loading Rate
2) Operating temperature
3) Nitrogen Loading

Putting aside all the biological permutations and bacteria families, in simple terms, bacteria thrives in a stable environment.
Bacteria has a relatively short life.
Bacteria can be fairly easily killed-off (or mutated)

So, we need to ensure we provide the right environment inside the tank for them to thrive.

Taking mesophile bacteria as an example, they thrive between 15-45 degrees, optimum is 37.

They need there own space, so an Organic Loading Rate of 3.75 kg/VS per m3/digester space is ideal.

The retention time should not exceed the slowest growing bacteria life.

To provide there own space and a low Organic Loading Rate needs big tanks.

Higher loading rates and smaller tanks means different operating temperatures and bacteria (thermophile)

As nitrogen is released during the process (and turned into ammonium) this inhibits the bacteria, therefore some high N feed-stocks may need to be processed at lower temperatures and longer retention times.

So, in a perfect world every type of feed-stock would have it's own profile (temperature, OLR, HRT, N loading) which of course is not possible.

Therefore calculating the optimum environment needs done correctly as compromise has to be made.